• Historical build-up:
  • hunting and megafaunal extinctions
  • agriculture and domestication
  • urbanization and population growth

• Current trends (today’s topic)
  • land use change
  • pollution
  • globalization

• Equivalent to a natural stressor if an organism’s response is similar or identical

• Agricultural intensity must match demand

• Freshwater is a limiting resource

  • 40% dedicated to agriculture

  • deep water sources are needed
  • water needs to be diverted

• Minerals and metals are needed for everything

• Natural ecosystems provide materials
  • and get it the way

• The impacts of globalization on natural systems is huge

• Humans move species around - for better or worse
  • necessary for food systems
  • unintentional has part of trade (invasive species)
  • intentional with unknown consequences

• Infrastructure of globalization also disrupts natural systems
  • roads fragment landscapes
  • transportation pollutes
  • politics of trade divides wealth

The radiative balance can be perturbed by “forcings’

• Each ‘forcing’ can alter:
  • incoming solar radiation (shortwave)
  • solar radiation that is reflected
  • longwave radiation emitted from Earth

• Forcings largely a function of greenhouse gases
  • each absorb longwave radiation

• Global mean surface temperature has risen ~ 1 degree C over the last 100 years

• How much is left to come?
  • depends on continued forcing
  • we can predict (based on trends)
  • always some uncertainty

• Global mean surface temperature has risen ~ 1 degree C over the last 100 years

• How much is left to come?
  • depends on continued forcing
  • we can predict (based on trends)
  • always some uncertainty